Computers are frequently used to generate documents that, when complete, are printed on paper using attached printing devices. For a variety of reasons, it is often difficult to discern exactly how such documents will look when printed without actually printing them. The most prominent reason is that, for a computer user to manipulate a document during generation, detailed elements within the document must be displayed large enough for the user to be able see and alter them. As a result, during generation, the display is filled with a small portion of the document, which is out of context with the remainder. Further, during generation, because of display resolution and processing time constraints, a document is sometimes displayed in a different format than the format in which it will later be printed.
FIGS. 1 and 2 illustrate differences between a printed document and its display image during generation. FIG. 1 is a document generated using Microsoft Word for Windows in final printed form. It shows a newspaper-style masthead 104, columns 105-107, and text sections 108-109. FIG. 2 is a display image of the same document during generation. It shows borders 201-203, columns 205, and a text section 208. The display is different from the printed page in a number of ways: 1) It shows borders 201-203, not present in the printed document. 2) It does not show masthead 104 of the printed document. 3) It does not show columns 106 and 107 of the printed document. 4) It does not show section 109, nor columns 106-107 of the printed document. 5) Page breaks are shown as dotted horizontal lines, not separate pages.
To allow their users to ascertain what documents will look like when actually printed, some application programs include either a "page preview" feature or a "reduced size" feature. The page preview feature presents one or two pages of the document in the same format in which it will be in when printed. The reduced size feature allows the user to generate the document at a lower than normal magnification factor, permitting more of the document to be displayed at once.
FIGS. 3-4 are display images illustrating an implementation of the page preview feature. FIG. 3 is a display image illustrating an implementation of the page preview feature. It shows a page of the document from FIG. 1, including a newspaper-style masthead 304, columns 305-307, and text sections 308-309. Implementations of the page preview feature display the entire page, as it will look when printed, theoretically allowing a user to see the context that a section of text will appear in, as well as the overall alignment of sections of the page. However, because of the low resolution of currently available display devices, displaying the entire page makes most of the text illegible.
Further, when running in an environment in which applications' output is displayed in resizable windows, implementations of page preview do not adjust the magnification factor at which they display a page in response to window resizing, limiting the fraction of each page that can be examined using page preview. FIG. 4 is a display image illustrating an implementation of the page preview feature with window size reduced. It shows a first window 401, in which an application is displaying a page 402 of a document in page preview mode. The first window has been resized to accommodate a second window 403. As a result, the lower half of the page displayed in page preview mode in the first window is obscured. Using implementations of the page preview feature, there is no way to view the lower half of any page in a window sized as the first window is.
Also, implementations of page preview display a maximum of two pages simultaneously. This limitation causes a problem where the document generated extends significantly in two dimensions, instead of just one. Examples of such two-dimensional documents include spreadsheets, project planning charts, organizational charts, and circuit diagrams. When previewing two-dimensional documents, the simultaneous display of several pages in each dimension may be necessary to determine context.
FIGS. 5-7 are display images illustrating an implementation of the reduced size feature. FIG. 5 is a display image illustrating an implementation of the reduced size feature in "normal mode." In normal mode, the document appears in the form in which it will be printed, but only about two-fifths of a page, section 501, is visible at once. It shows part of the first page of a document during generation, which contains text section 501. FIG. 6 is a display image illustrating an implementation of the reduced size feature in reduced size mode. It shows parts of the first two pages of the same document during generation in reduced size mode, including text sections 601-603. FIG. 7 is a display image illustrating an implementation of the reduced size feature in side-by-side mode, as well as reduced size mode. It shows parts of the first three pages of the same document during generation, including text sections 701-704.
In reduced size mode, about one and one-fifth of a page, sections 601-603, are visible, and the text is somewhat legible, but certainly not clear. When not in side-by-side mode, pages appear in a vertical column. In reduced size mode and side-by-side mode, pages appear in two vertical columns, and about one and one-fifth of a page is visible in each column. A maximum of two full pages and up to four fractional pages can therefore be displayed at once, which can be inadequate for reasonably large two-dimensional documents.
Like implementations of the page preview feature, implementations of the reduced size feature do not adjust the magnification at which they display the page in response to window resizing. This limits the fraction of each page that can be examined at once using the reduced size feature.
Both the page preview feature and the reduced size feature have significant shortcomings as tools to help ascertain what a computer-generated document will look like when it is printed. Neither shows text or other page contents in a completely legible way, neither resizes the image to fit in a resized window, and neither can display more than two whole pages simultaneously on a normal display device.